The purpose of the proposed project is to establish a plasma membrane preparation derived from skeletal muscle suitable for the investigation of the insulin-sensitive hexose transport system. The basic criteria which will be used to establish the suitability of such a preparation for these studies will be: (1) a pure membrane preparation relatively free from contamination from other subcellular sources, (2) membranes which exhibit a stereospecific, facilitated diffusion of D-glucose, and (3) membranes which exhibit the high affinity, specific receptors for insulin that are generally associated with insulin action. Once such a preparation has been obtained we will seek to kinetically characterize the hexose transport system in plasma membrane vesicles. This will be followed by the identification and isolation of the molecular components of this membrane involved in this process by means of various membrane fractionation procedures. Transport activity, once removed from the membrane will be monitored by reconstitution of this activity into exogenous phospholipid vesicles. Concurrent with these procedures, we will attempt to biochemically characterize many of the lipid, carbohydrate and protein constituents of this membrane through high resolution analytical methods such as two dimensional gel electrophoresis. These proposed studies should provide a basis for future investigations into the mechanisms of insulin action in regard to the regulation of hexose transport activity.